Build Your Own Clone Message Board

Hey There,

I'm sourcing parts for an upcoming build and I wondering what effect voltage has on caps.

100v and 50v seems to be the most common but what about all the other volts? How do I decide what I need? I've been having trouble tracking down what I'm looking for:

2.2uf, 4.7uf, 20 uf, 10nf, 47nf, 100nf.

The uf caps will have to be electrolytic caps, yeah? They will be used for input and out put caps.

EDIT:
Ok, I figured out that 10nf = .01uf, 47nf = .047uf and 100nf = .1 uf.

How do I choose what voltage I want?

easy, just choose a voltage higher than the max input voltage of the circuit. So, if you're running at 9v+ like from a battery or a standard pedal power supply, just choose the next size up (usually 16v or so). If you want the ability to run at higher voltages, then you'd use the next bigger size than the supply, like 25v caps for an 18v supply. Of course any cap with a max voltage rating higher than your supply will work... but with bigger voltage ratings usually comes bigger size, so you want to keep them as small as possible while still maintaining a healthy safety margin. Make sense?

I simplify it Hag. I shoot for 25v all the time. If they don't have or are out I shoot for 35 or 50. The reason is that I don't want to carry 16v as I'm starting to run some circuits on 15-18v and I don't want to keep two different stocks, one for my 9v pedals and one for pedals above that. I'm also afraid I'll make a mistake, forget, put a 16v cap in my 18v pedal. But, that is just me.

You will begin to memorize what a electo cap value likely is vs. film cap. But you can always use the layout to see whether it shows you a circle for the electro or a rectangle for the film caps...if you are not sure.

I guess you know electro's are polorized and must be installed correctly. Film are not and can go in, in any direction.

Yep, thanks guys, makes total sense!

One thing I'm wondering, I see electro caps and film caps come in some same sizes. If I have the option, typically do I always want to source film caps ahead of audio grade electrolytic caps?

Also, this design calls for a 2.2uf input cap and 20uf output cap. I'm only finding those as electro caps. So for the input cap - generally one leg connects to the input and one leg connects to the transistor base. For the output, one leg to the emitter and one leg to the output. Which side should be pos and which should be neg? In my experience I've always used non-polarized caps for input and output.

Thanks guys!

When sourcing film vs. lytic, you need to source (most of the time) for what the build calls for. Again, go to the layout of the pedal where each component is numbered on a pic of the board. The outline of the cap tells you what you want.

The two values you show are electrolytics. "Generally" the long leg is the positive and short negative. Where what goes depends on the schematic. The layout pic I mention above will almost always have a + and or - so you know.

You are not doing a point to point right?

Thanks,

Yeah point to point on perf board with that fuzz face project I posted about. The input cap is 2.2uf and the output cap is 20uf so those have to been electrolytic as far as I can tell...

Ah, ok. On the schematic the caps are drawn as I( so that means pos to input and neg to base.

Oh, you are doing PTP. I get it now. I'm a little slow

My (somewhat limited) experience is that anything over 1uF is Electro, anything under is non-polarized. It is only really the 1uF ones that you have to check on, and if I am remembering correctly, you can always use polarized (electro) instead of non-polar as long as you orient the polar correctly, but you cant go the other way (use a non-polar for a polar).

For your fuzz face, is it positive or negative ground (PNP or NPN)?? This will determine what direction the electro's go. From your last post I am assuming PNP, in which case you have it right, positive lead of the cap goes to input, neg to the tranny. This would be opposite for a NPN.